Heat transfer



Nov. 1s, 1941. H.A.-BUR;GRAB 2,263,067K

HEAT `TRANSFER Filed Dc; 15, 1937 k `s Sheets-sheet 4 A rbc/way Patented 18,A '19.4.1

' systems now in use.

I stallations.

six sheets, and wherein .1 Fig.- 1 is a diagrammatic lay-out UNITED 'STATES PATENT oFF-ICE .2,263,067 i HEAT TRANSFER 'Henry A. urggrabe, Detroit, Mich., assignor to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Application `=December 13, 1937. Serial No.

`f (Cl. 62-5) i Fig. 6 isa side elevation taken along `the line 16 Claims. This invention relates to the art of refrigerajtion\ and has particular reference -to anew and improved methodof and apparatus for producing refrigeration` through the agency of an absorption system.

A princ' (al object of the invention is `to pro- `vide a refrigeration system of the absorption i type, particularly adapted for use in household refrigeratorsand which is more simple in construction andl more eilicient in operation than Another object or theinvention Ais, to provide an absorption system wherein the refrgerating `periods are relatively long, with the result that the system will give a performance comparable with that. of continuous absorption systems now in use. 4

Another object of the invention is to provide l 4an absorption system of the two-pressure type in which refrigeration is produced 'almost continuously in the evaporator and inwhich system the pressures are periodically balanced between the absorberend the generator for a. relatively short time so as to effect the transfer of liquor therebetween.

. Another object of the invention is to provide A that improvement in a. two-.pressure absorption system wherein pressure is utilized for periodically-'effecting the transfer of liquor between the absorber and the generator systems.

Another object of the invention is to provide ang-improvement inthe art rof absorption rej frigeration wherein the circulation of fluids with- `in the systemis effected by pressure, with the re V sultthat parts of such system may be arranged in various ways and-.at various levels relative to each other, thereby simplifying the problem of fusing such` a system invarious types of in- Other objects and advantages of this invention `will be apparent from a consideration of the following specification taken -in conjunction with f the accompanying drawings, ofwhich there are of an absorption system embodying my invention;

Fig. 2 is a diagrammatic view` illustrating a modied form of control;

Fig. Sis a'view illustrating the application oi a vsystem. embodying my invention to a refrigerator "cabint oi, ,the household type;

' Fig. 4 is a horizontal section taken in the plane along the imei- Q4 oi.Fig.3; i

Fig. 5 is a' front elevation of the evaporatorV i c employed-m the cabinet mustradin F153;

5 Fig. 8 is a partial top plan of `6--6 of Fig. 5 of the evaporator;

Fig. 7 is a front elevation of the apparatus taken along the line 1-1 of Fig; i3;

of the apparatus illus- 7 and taken along the line 9-9 Fig. 12 is a vertical section through the trans-V fer chamber and taken on the line I2--I2 of` Fig. 8; i y

Fig. 13 'is a vertical section. through the high side iloat and `tal-ren in a plane along the line l3-l3 of Fig. 4;.and Fig. 14 is a horizontal transfer valve mechanism and taken in a plane on the line M-M of Fig. 12.

Referring now to Fig. 1 wherein the system is "illustrated somewhat diagrammaticfally, lthe sys- -a generator or generating system 2l and a condenser 26, all of the parts being connected in a closed circuit and being charged with any suitable absorption medium, such as a solution of ammonia and water.

The `generator' system 2l includes a `receiver 28 comprising in its upper region a oat chamber and in its lower region a reservoir, an analyzer SIL-a heat exchanger 32, a boiler 34, a percolator, thermosiphon, or vapor lift coil 3B, a source of heat, such as a gas burner 38, and a vent l0 betweenthe upper end of the iioat chamber-28 and the analyzer 30. The upper end of the .analyzer In is connected by a rectier 42 and a check valve controlled conduit 44 to the condenser system 26. The condenser system 2B includes a condenser 46 and a high side oat I8. The high side float is connected by a liquid reevapora'tor' 2U, and the exhaust side of the evaporator 2U is connected bya suction line i2 to the'absorber systemen. if

The absorber system!! comprises a header ll, v a vertically arranged pipe IB, communicating at its upper end with thebottom of .the header M anda finned coil 5I connected at its bottom end tothe loweruportion of the pipe 5l and atV its upper end to the upper part of the header 8 4.

The suction line 5 2 from, the evaporator termi- 5, naiss in an upwardly rising portion sa, having s the apparatus section through the tem comprises an evaporator 20, an absorber 22,

frigersnt conduit n to the intake side of the the burner 88 from .chamber 28. The bottom of the float chamber 26 is connected with the bottom of the boiler 34 by a weak liquor line 68, whichforms one part Y of the heat exchanger 32, and an upper part of the oat chamber 28 is connected by a strong liquor line 10, which strong liquor line forms a partof the heat exchanger 32. The percolating coil 36, at one end thereof, is connected to the bottom of the analyzer and the other end thereof opens into the vapor space inthe boiler 34. The vapor space in the boiler 34 is connected by a conduit 12 to an intermediate part of the analyzer, said conduit 12 terminating below the l liquid level in the analyzer 38. 1

During the heating cycle,lgas may be supplied to the burner 38 through a thermostatic control valve 14 and past a-safety shut-off valve 16. The safety shut-off valve 16 will operate to shut off the supply of gas to the burner 38 in the event `the flame thereof goes out, The thermostatic control valve includes a thermo-responsive element 15`thermally associated with the tail end of the evaporator coil ,20. -The thermostatic control valve 14 may beset so as to pass a predetermined amount of gas at all times in order to provide a low'ame in the burner 38, and when the temperatureof the evaporator 20 rises above apre-selected degree,A thevvalve 14 will open to pass a predetermined larger quantity of gas so as to produce a high flame inthe burner 38, or the valve 14- may operate to modulate the gas supply above a predetermined minimum and in accordance with the temperature of the evaporator 28. 'I'he system/appears to work satisfactorily, however, if the valve 14 has only `.two positions which will supply a low or high quantity of gas to the burner to produce a low or a high ame. When the temperature of the evaporator 20 drops below the temperature setting of the valve 14, vthe valve will operate to cut the supply of gas to the burner down to the minimum.

In Fig. 2 there is illustrated a modified form of burner control useful in connectionwith a kerosene burner. In this modification. a kerosene burner 80 is adapted to supply heat to the absorption system, and the supply of kerosene to a reservoir 82may bel controlled by a float controlled valve 84.'. A manually controlled valve 86 may be used between the float control 84 and the burner 80 for regulating the amount of fuel supplied to the burner 80 and thereby rmodulating the flame thereof. With this `kind of a control, the user of the absorption system could regulate the amount of heat supplied to the system so as to produce whatever refrigeration was desired within the limits of the capacity of the systems are illustrated as such levels are at the beginningof. a generating cycle. .The float charnber 28 is filled to' a level 88; the analyzer contains liquid to a level 88, corresponding to the level of liquid in the float chamber and liquidA stands in system;` l Of course, a thermostatically controlled valve, like the valve 14', might be employed in connection with a kerosene burn the lboiler 34 at a level 90, which corresponds with the `level of the lower end of the tube 12 in the analyzer 38.. The analyzer 30 and the float chamber 28 are in open communication, and the liquid therein will stand at the same level, while the liquid in the boiler 34 will stand at a lower level, due to the pressure head required to force vapor through the tube 12. The conduits 62, 64 and 66, connecting the float chamber 28 with the absorber system,- are closed by the valves 63, 65 Vand 61 so that the generator system 24 is closed from the absorber system 22.

At the beginning of the generating' cycle, the generator system is charged with strong liquor which'stands therein to the levels 88 and 90.

The addition of heat to the generator system by the burner 38 will result in the evolution of ammonia gas. The percolating coil 36 is ar'- ranged above the burner 38 so that the contents of the percolating coil 36 are heated. Heating of the percolating coil 36 will cause the liquor within the coil 36 to percolate, that is, heat will drive the ammonia vapor out of the ammonia water solution and the vapor will rise in the percolating coil 36 carrying the liquor along with it into the upper part of the boiler 34 where the liquor spills over into the bottom of the boiler 34, while the vapor is forced through the conduit 12 into the in the generator system being higher than the 3.', pressure in. the condenser system. In the boiler 34, the liquor therein is also subjected to heat so as to aid in the expulsion of ammonia vapor from the liquor and the liquor, after the expulsion( of ammonia therefrom, being weak liquor,

4o will'return by gravity through the conduit 68 to the lower part of the oat chamber' 28. Since ammonia liquor is pumped through the ercolating coil 36 from the bottom part of e analyzer up into the boiler 34, liquor will ow 4..) from the upper part of the float chamber 28 through the conduit 18 into the analyzer from whence the liquid is taken through the percolat` ing coil 36 into the boiler. The weak liquor, in returning to the float chamber 28 through the u 7conduit 68, will pass through the heat exchanger 32 for transferring heat from the hot weak liquor to the cold strong liquor which is flowing through the conduit 10 into the analyzer 38. Likewise the bubbling of the ammonia vapor, after leaving the tube 12, through the analyzer 30,.will serve to cool the ammonia vapor and tend to effect the condensation of water vapor out of the ammonia vapor. Further, the ammonia vapor passing through the rectifler 42 will also tend to pre- U cipitate water which will drain back into the analyzer. -The rectifier 42 is illustrated as being -an air cooled rectier. The transfer of strong liquor from the float chamber 28 to the boiler 34 and weak liquor from the boiler 34 to the float chamber 28 will continue, due to the pumping action of 'the percolating coil 36,

of liquid in the Vfloat chamber and analyzer falls to the level indicated at 92, and at which time m the liquor in the generator system will be weak liquor.v 'I'he ammonia vapor driven out of the liquor in the generator system, in"r until the level the flow of ammonia liquid to the evaporator vaporization ofthe ammonia liquid takes place and the ammonia vapor is returned to the absorber system through the conduit 52. `The pressure in the` condensersystem' will be less than j the pressure in the generator system,.due.to the dissipation of heat from the ammonia in the con- 20, through the conduit 50. Inthe evaporator 20,

denser system, andthe high side iioat 43,- when closed, effectively separates th"e condenser sys-- tern from the evaporator system, wherein thepressure is lower than in the condenser system. The pressure in the absorber system, duringthe evaporator system so ammonia vapor will ow through the conduit 52 into the absorber system past the check valve 50. The ammonia vapor returned to the" absorber system will enter the ilnned coil 58 and effect a circulation of liquid by a percolating action inthe absorber .upwardly `to the bottom end of the coil 58. In this manner, absorption of ammonia vapor into the liquor in the absorber is promoted and the heat of absorption is dissipated by the finned coil 58.`

At the ,end of the generating cycle, the level of liquid in the iioat chamber 28, having fallen to level 32, will lower Afloat 34, which will open the valve 51. 'I'he mechanism by which the valves c 53, 55 and 51 are controlledby the iioat 94 will be described in detail in connection with Fig. .12. Due to the fact that the pressure in the generator system is higherthan the vpressure inuthe absorber system, the weak liquor in the generator system will be forced through the conduit 56,

afterthe opening of valve 61, into the absorber system, thereby raising the levelof liquid in the absorber.' The weak liquor. being heavier than the strong liquor, will tendto remain in the botthe float chamber, all oi' the liquor `in the ana- 3 feet that 'the transfer period 1s relatively snort.' the burner 38 can continue to operate without any great amount of loss in eiliciency,` and during' ythe transfer period theperco'lating coil 35 and the bottom part of the analyzer will contain am monia liquor, and hence,` during the operation. of the apparatus, the generation V of 'ammonia vapor will be continuous. i

In Figs. 3 to i4 inclusive, 'an apparatus `em- I bodying the system illustrated in Fig. 1 is illus-` trated, as applied to a refrigerator cabinet ofthe household type. The cabinet comprises a heat generating cycle, is still lower than that in the throughxthe' coil 53 into the upper part of the header 54 anddownwardly through the pipe 56 ofthe apparatusfcompartment may be remov-` -tom part of the absorber. 4All of the liquor in I `lyzer above the bottom of conduit 10, and all of the liquor in the boiler 34 above the conduit 53 will ,pass through the conduit 66 into the absorber and so soon as all of such liquor has been expelled from the generator system, vapor will y pass through the conduit 55 into the absorber system, thereby equalizing the pressure between the absorber system 22 and the generator system'. So soon as the pressure in the generating system and the absorber system isequalized, the valves 63 and 55 will open, whereupon strong liquor will-now by gravity through conduit 54 from the absorber into the iioat chamber 23 and the vent 62 will permitfsuch gravity now; Liquor `will continue to flow into the iloat chamber 23 until the level therein reaches level 03, whereupon oxait 34 will operate to seat valves 63, 55` and 51,

,therebyv separating the generator system from 'the absorber system, and thegenerating cycle The period during which the valves 33, 55 and 51 areopen V11n-ay, be' designated asthe transfer. period, andthis p'eriod is will `then commence.

relatively short; say in the neighborhood of two or three minutes, whereas, l'the generating period insulated provision compartment |00 and' an apparatus vcompartment'. |02 arranged beneath j the provision compartment, a suitable cabinet having insulated walls and a sheet metalexterior providing these compartments. The provision compartment `|00 is provided with an ac cess -opening and a door |04 for closingvthe same, and an evaporator |20 is arranged centrally and adjacent the upper end of the provisioncompartment |00.

structed to providea ilue |0 3 at the rear thereof, f

The cabinet is conand the generator, absorber and 'condenser are assembled as an integral unit and arranged withvin the apparatus compartment |02. 'I'he front able so as to provide access to the apparatus.

The unit which includes the absorber, the generator. the condenser and the rectifier is il- `lustrated` in Figs'. 7 to 11 inclusive, and to faciliillustratedY in Figs. 3 to 14 inclusive, the same reference `characters will beused to indicate ther elements of the system'as areused in connection with Fig. l. yReferring to Figs. 'l to 1l.in

a'- vertically arranged tubular header having a plurality or tubes m extending therethrough and fadapted to provide fiues. The spiral partof the percolating coil 36.` is arranged below .the tlues in the boiler 34, and the lower end f the percolating coil communicates with t lower end oi' the analyzer vessel 30. A sleeve |35 may the conduit 12 tothe analyzer, said conduitex-Jl tending downwardly into the `analyzer to about the middle thereof. The boiler 34 and the analyzer 30 are enclosed in .The unit which comprises the absorber, the

generator, the condenser and thelrectitler is carried by a box-likeframe which comprises a pair of `side frame members4 |43, closed at one side by a wall |44 and connected at the bottom` 5 by frame members |45.` The boiler 34 is conmay, depending upon `the load upon the evap-l orator 20, last for about one-half hour or more. During the transfer'` period the check valvev 60 will seat, thereby preventing .the backing up of `the liquor into the evaporator system, and during l the'transfer period, evaporation. of ammonia in the evaporator may cease, 4if the vaporz'pressurel I inthe evaporator rises" above that at which evaporation o! ammonia can take place'. Due to the nested byglbracket |45 to the wall |44 so' as to be carried tlreby,and the iiue |33 extends through 1an' openingin the wall |44. The compartmentdeilned by thewalls |33. |40', |4I and |42 also is carried by the wall |44.I The heat exchanger also is arrangedlwitliin the com` partment around the b'oiler and comprises a double coil o1' pipes 'I0 and "53: disposed around the -boiler and the analyzer. One end of the coil I0 is connected to an intermediate part or the tate an 'understanding of the construction asl clusive,`the.boi1er` 34 is illustrated as comprising` la compartment formed then connects the rectifier with the condenser- 48. The condenser 46 is illustrated'as comprising a continuous coil supported by the end frame members |43 and having fins |48 to increase the heat dissipating capacity of the coil. The condenser coil slopes toward one end so as to collect condensed ammonia in such end, and this end of the condenser coil is connected by a conduit 49 to the high side float 48, which is arranged in the wall of the cabinet behind the evaporator |20. The ,suction line 52 leading from the evaporator to the absorber may be arranged in good thermal contact with the liquid line 49, and such lines may be arranged within the flue |06. The suction line 52 terminates in a valve body within which a check valve 60 is a1'- ranged, and through the Valve body the suction line 52 is' connected to the finned coil 58, which constitutes a part of the absorber. The finned coil 58 is horizontally arranged above the condenser 46 andsupported by the end frame members |43, and the upper end of the finned coil 58 is connected by a conduit |50 to an upper part of one of the headers of the absorber. In practice," the absorber may be providedwith two headers 54a and 54h, and the conduit |50 is adaptedto discharge liquor into the upper end Aof header 54a and into a horizonta1 trough |52 arranged in such header 54a. The liquid discharged from the conduit ,|50 `will overflow the trough |52 and spill over into the bottom of the header 54a. A conduit |54 connects the bottom part of the header 54a to an intermediate part of the header 54h. The coil 58 is finned to eX- pedite the dissipation of heat, aiding the absorptlon of ammonia vapor in the weak liquor.

-In addition to the headers 54a and 54h, and the f Coil 58, theabsorberj comprises a small header |58 arranged at the top ends of the headers 54a and 54hA and in communication therewith by means of conduits |60. The upper end of pipe .56 passes through the lower partof header 54h wherein it is perforated and terminates in header |58. The valve controlled conduit 66, which conducts weak liquor from the float chamber 28 to the absorber, terminates in a horizontally arranged distributor pipe |62, arranged' within header |58. The valve controlled conduit 64, which conducts strong liquorfrom the absorber to the float chamber, is Ain communication with the lower part of header 54a, and the vent 62 between the float chamber 28 and the absorber terminates in a distributing nozzle |64 which extends through the trough |52. The ends of the nozzle |64 project through the end wall of the header 54d and forma support for the trough |52. Ammonia, vapor returning to the lation of liquid upwardly through the coil 58,-thc

conduit and into the trough |52', thence the A absorberffrom the evaporator will effect a circudownwardly into conduit |56 and back to the 7'5 bottom of coil58. Such circulation within the absorber will promote the absorption of amvpasses through the valved conduit 66 into the absorber, is conducted by the conduit 66 and the perforated distributor |62 into the header |58, thence into the end of the pipe 58 and thence through pipe 56 into the header 54h, as well as downwardly through the pipe 56 into the lower part of the coil 58. By bringing the weak liquor from the float chamber 28 into the absorber in this manner, such weak liqubr is kept separate from the strong liquor in the header 54a which is about to be transferred through conduit 64 into the float chamber 28.

The vent 40 affords communication between the upper part of the analyzer 38 and the upper Dart of the float chamber 28 so that the pressures and the liquid levels in these two tanks areequal.

|68 to the vent 40 and -at its lower end by conduit |10 to conduit 10. This chamber |66 provides additional reservoir or storage space for strong liquor coming into the oat chamber 28 ifrom the absorber;

Referring to Figs. 12 and 14, the float chamber 28 is provided with three valves, 63,65 and 61, which are operable, atleast in part, bythe oat 94. The float chamber'28 comprises a vertically arranged header having float 94 therein.

'I'he float 94 is guided upon a vertical post |12, the upper end of which is secured in a boss |14 in theupper end of the header, and the lower end of which post is held by bracket |16. The oat -94 is provided with a sleeve on its axis which telescopes post |12 and guides the float '94 upon movement thereof, responsive to changes in 4liquid levels in the float chamber 28. The float 94 may have a scavenging tube |18 extending into the bottom thereof so as to utilize changes in pressure within the chamber 26 for expelling any liquid which might leak into the nismcomprises an arm |86 carried by the bot-` tom of float 94, a lever |88 having a pivoted connection at one end thereof to the end of arm |86 and a pin and slot connection |90 at the other end thereof to a bifurcated bracket |92,

a lever |94, pivoted at |96 to a-bracket |98, andl having one end thereof pivoted at 200 to lever |88 and the other end thereof provided with fingers 202, engageable with a collar 204-carried by valve stem 206 o'f valve 61. 'Ihe colla'r 204 is set on the valve stem 206 so that the ngers will not engage the collar 204 until after the lever |94 has moved a considerable distance. The valve stem 206 carries a needle valve 208 cooperable with a seat 2|0 carried by a fit g 2|2 which projects out of the oat chamber 28 and to which the end of conduit 66 is connected. The needle 208 and seat 2|0 comprise the valve An auxiliary reservoir or tank |66 may be connected at its upper end by a conduit- 61 which controls communication between the conduit 66 and the interior of the 'float chamf ber 28. y

Valve 65 comprises a needle 214 mounted for vertical movement in .a guide 216 and` havinga dthrough conduit 615, vapor will pass through such conduit and thereby permit the equalization of e pressure between the o'at chamber 28 and the spring' 218 between the guide 216 and the collar 226 carried by the stem of the needle 214 for .biasing the needle 214 o ff of its seat 222. The

seat 222 is pressed in a bushing 224 which provides lter chamber 226, in which a filter v'228 arranged, and the bottom of bushing 224 is closed by a lplug 236. Conduit 64 is connected to "one side of the bushing 224 and the needle 214, and .seat 222 controls communication be` tween the conduit 64 and the interior of the float chamber 28. The needle is held on its seat by a lever 232, a part of which engages the end of' the stern of the needle valve 214. The lever 232 is pivoted to bracket 116 at 234 and is provided at one end thereof with a finger 236 which engages a notch in a plate.238 at one end absorber. chamber 28 and the absorber is substantially equalized, theneedle valves 214 and 254 will be' When the pressure between the oat come unseated, the spring 218 operating lto unseat needle valve 214 and gravity operating'to unseat needle waive 254. The opening of valve 63 will vent the upper part of float chamber to L the upper part of the absorber soas to permit strong liquor to flow from header ,54a through l conduit 64. and past valve 65 into the float chamof the spring 246. Lever 184y also is formed to provide a finger 242 which engages in a notch in another plate 244 at the other end of spring 246. The spring 246 is adapted to snap theelever 232 from one of its positions to the other and in the position illustrated in Fig. 12 the spring 246 holds lever 232 in sucha position 'so as` to hold` needle valve 214 on its seat. The other end of lever 232, which'is bifurcated, is arrangedbetween apair of collars 246 and`246fcarried by a shaft 248. Shaft ,248 is guided at one end thereof for vertical movement by a' guide bore 256 formed in the casting 186 and extends through a sleeve 252 formed in float 254 and has xed to the Vend thereof a needle valve 254.

T he lower one of the collars 246 is pinned toA l the shaft 248, while the upper one of the collars 245 is lbacked up by a spring 256, which spring 'is backed upv by a-`stop 258` xed to the shaft. l

.In addition'to the needle 254, the valve 63 -comprises a seat,2 66 carriedby a-tting 262' pressed into a bushing 264 carriedby a. boss 266 formed in the end 4of the float chamber header. In Fig. 112, the valves are shown inhtheir closed position, and the: float 94 is shown inits high position. When the level` of the liquid'inV the ber 28. It will be observed at this point that the' relative dimensions of the conduits 64 and 66 and? the valves 65 and 61 is such thatv considerably more liquor can be transferred by conduit 64 than by conduit 66. The manner in which' the f operate to actuate the snap-acting toggle mech` anism so as tolpositively seat'the valves 63 and 65, while the valve 61 will be seated by spring 265 so soon as the lever 194 moves.

pressure in the generator system .will increase, due to the' fact that heat is being added to the liquor in the generator system by the burner 86.

In Fig.` 13 the details of the high side maus are illustrated., The high side oat 46 comprises va shell ,216 having a vertically arranged stationary shaft 212. A valve body 214 is connected to the .lower part of the shell 216 and hasa passageway therethroughin which aeseat 216 for needle valve 218 is disposed. The needle valve ,l

218 is adapted to be actuated by a lever` 286, piv- -oted at -282' to a part of the valve body 214. A

float chamber 28 falls, armv |86 will move 'lever' 188 and lever 1194. When .the'floatl reachesth low liquid level in the float chamber 28', lever 164 will raise needle valve 268 olf its seat, there by opening valve 61 and establishingcommunication between the float chamber 28 and the absorber, and the nger 242 will be lower than the linger 286, whereupon spring 246, will snap lever 232 to its otherpositioraf At this point, the

chamber .28` will force the weak liquor in the generator system into theabsorber through the conduit 66. When the snap-acting toggle mech-` ypressure in the generator .system andthe oat anism is operated, the lever'232 will move away from the end of the stem of the needle valve 214 and will also'move shaft 248 downwardly;A *l'The upper end of the shaft 248seats within'a, f `socket within the needleA valve254, but is not 'cbnnected thereto, so thatiwhen `shaft`248 is moved downwardly by lever 232 the needle valve 254 will be held on its seat, due to the difference in pressure prevailing'between the float chamber 28 and the'absorber. Likewise, due tothe pres- I float 282, guided by the shaft 212 andhaving aA scavenging tube 284, such as the scavenging tube 118, 'is provided .with alcollar'286 which-'engages a slot 288 in theiever 286 for actuating the same uponmov'exnent of the float 282, responsive to ychanges in level of liquid within the shell 216. The high sido float is connected to receive liquidfrom the [condenser through conduit andthe endl of the valve body 214 is connected the evaporator by a conduit 56.

The evaporatorv as illustratednFigs. 34," 5

an'd 6 comprises a sleeve 366 closed at its back and adapted to be` closed at its front by a door 362and a coil of tubing 364 coiledaround the sleeve 366 and secured in good thermal contact therewith. i Fins 366 may be employed for increasing the' heat exchange surface of the evapof rater. The tail end 368 of coil 364 discharges into a horizontally -arranged headerv316, and sncf'- tion or vapor Vreturn line 52 extends into the header 316 and terminates inv a well 312 formed therein. #The well 312is adapted to collect what. Y

ever water may collect ,1in the evaporator, and v f so soon as; the-waterrises in the well 312 above the end of suction line 52 the pressurein the evaporator will force a slug of water through the vallssipating capacityI thereof.

sure differential between therfloat chamberA 28 i and the absorber, needleC valve 214 will be held `upon its seat. After all ofthe weakliquor vbeen ,dischargedy from the 'float chambe `conduit -52 back ,to the absor er. 316 may be finned at 314 to` The header The header 816 is employed so las to prevent frosting back of the ysuction line 32. -A capillary tube 318 may be are ranged in the conduit 56 between `the high side .c 4float 48 andtheev/apora'torso astc preventxthe After the valves .63, 65, and 61 are closed, the

crease the heat i evaporator |20.

expansion of ammonia liquid prior to entering the evaporator. This capillary tubev also will serve to cut down the pressure drop at the needle of the high side float 48. As illustrated in Fig. l, a control bulb, suchas a bulb l5, may be mounted upon the evaporator for operating the thermostatically controlled valve which supplies fuel to the burner.

The unit comprising the absorber, the generator, the condenser and the rectifier is adapted to be arranged within'the apparatus compart- `ment |02, and to ,this end the bottom of the apparatus compartment may be provided with a pair of side rails 320 upon which the ends of .the bottom frame members |45 of the unit are adapted to rest. As will be apparent from van inspection of Fig. 3, the unit is arranged to project slightly out theback of the apparatus compartment, and the back of theunit, above the` bottom of the condenser coil |48, is adaptedthe space therebetween so as to define a flue of rectangular cross section at the back of the refrigerator cabinet. The laterally extending flue |38,Vthrough which the products ofcombustion from the burner pass, empties into a vertical flue 326 which is open at the bottom, so that, fresh air passes upwardly in the flue 326 with the ue gases to aidA in dissipating the lheat thereof. While the top of the unitr'above the finned coils is open, the wall |44 terminates a very short distance below the underside of the bottom of the provision compartment |00, so as topermit a circulation of air upwardly through thaapparatus compartment 'and in contact with the float chamber 28, the header 54a, 54h and the conduits therebetween. The bottom of the apparatus compartment is open so as to also permit the circulation of air up through the bottom of the unit and past the nned coils of the condenser, the absorber and the rectier.

By removing the burner80, which may be.

bolted to the flange on the bottom` of sleeve |35, and by removing the back panel 324 of the flue, the unit including the condenser, theabsorber'and the generator may be removed from the apparatus compartment, and at the same `'time the evaporator |20 may be removed by moving the same laterally through the Lopening in the rear wall of the cabinet. In this manner, the absorption` unit may be manufactured, assembled and tested independently of the cabinet and installed therein and removed therefromy 'l without breaking any of the lines of the system.

The high side oat 48 is adapted to set in a space in the rear wall of the cabinet behind the 'I'he evaporatorv |20 may be mounted upon a removable closure 328 which CII closes the opening formed in the food tank linf.

ing 330, and'the high side float 48 may be securedto the rear side of such closure. `Preferably the space around thehighside float is Llled with'insulation.- A removable plate332 is secured to the back wall of the cabinetfor holding the insulation in place. The lines 49 and 52 may, pass through the cl'osure 328 in any suitable manner, such as by cutting notches 1n 75 the edges of such closure and sealing such notches with any suitable Apacking material.

' The apparatus illustrated in Figs. 3 to 14 inclusive, embodies the system illustrated in Fig. 1 and will operate in accordance with the description of operation given in connectionv with Fig. 1. n The system maybe provided with a suitable charging vvalve so as to permit the introduction of absorption fluid into the system after assembly thereof and with a safety device, such. as a fusable plug or rupture disc, so as to forestall any possible eXplosion thereof.

I While the invention has been described with some detail, it is to be understood that the description is for the purpose of illustration only and is not definitive ofthe limits of the inventive idea. The right is reserved to make such changes in the' details of construction and arrangement of parts as will fall within the purview of the attached claims.

ving means for said boiler, said receiver being separated fromsaid heating means so as not to be directly affected by the heat therefrom.

2. In an absorption apparatus, a generator system, an absorber system, said generator system including a liquid receiver and a boiler in open communication with each other, thermosiphon means for effecting a circulation of fluid between said receiver and said boiler and forming part of said communication therebetween, connections between said receiver and said absorber, means for closing said connections, and means in said receiver operable for opening said closing means, responsive to a change in the liquid level in said receiver for periodically effecting the transfer of iluid between said receiver and said absorber system.

3. In an absorption apparatus, an absorber system, a generator system, said generator sys. tem including a receiver and a thermosiphon generator, said receiver-being separated from the generator, heating means for the generator, connections between said receiver and said absorber system for periodically transferring fluid therebetween, valves in said receiver controlling said connections, said generator system including fluid I connections arranged between said receiver and said generator and including means for transferring heat from the hot weak liquor returning to the receiver to the cold strong liquor flowing to the generator.

4. In an absorption apparatus, a generator system, an absorber system, means for storing weak liquor in the generator system during the time that heat is applied to the generator system for generating refrigerant vapor, means for periodically transferringsaid weak liquor to one part of the absorber system and means for thereafter transferring strong liquor from' another 2 part of the absorber system to the generator sys-f tem, the -part of the absorber system to which said weak liquor is transferred being at a lower elevation than that part from which strong liquor is transferred to said generator system.

l rially less than thatof said generator.

for storing weak liquor in another part of the generator system at a temperature materially less than' that prevailing in `said other part of said generator system and-means for periodically utilizing pressure in the generator system for' transferring said weak liquor to the absorber y system and thereby equalizing the pressure between the absorber system and the generator system, so as to permit/the transfer. of strong liquor from the absorber system to the generator system.

. 6. In an absorption apparatus, an absorber system, a generator system, said generator system including a liquid receiver, connections -between said liquid receiver and said absorber system, `operable for venting said receiver-to said absorber system, transferring weak liquor from said receiver to said` absorber system and trans- I ferring strong liquor from said absorber system to said receiver, valves for controlling said connections, snap-acting mechanism for operating said valves and a iioat responsive to changes withinthe liquid level in the receiver for operating said snap-acting mechanism.

` F1. Inan absorption apparatus a generator system including a receiver and a continuous type of generator, means for circulating uid from said receiver to said generator and back to weak liquor flowing from the `generator and the cold strong liquor flowing to the generator.

8. In an absorption apparatus an absorber" system, a generator system, said generator sys-A tern including a thermosiphon generator and aA transfer device, said transfer device including a liquid receiver and being in open communication at `all times with the generator, said transfer device being adapted for. storing absorption iluidgand for periodically effecting the transfer of weak liquor therefrom to the absorber system andstrong liquor from the absorber system to the generator system, said transfer device beingv adapted to store fluid at a temperature mate- 11. In an absorption apparatus having a high pressure side and a low pressure side with aA generator system arranged .on the high pressure side and an absorber `system arranged on the low pressure side andv in which the pressure is periodically equalized between vthe generator system and the absorber system for effecting the 'transfer of iluid'therebetween, said generator system comprising heating means and a fluid circulating circuit including storage means havling a part for storingstrong liquor and a part 'said' receiver and including a heat exchanger arranged so as to exchange heat between the hot for storing weak liquor, thermosiphon means for effecting circulation of liquonbetween -said parts of said storage means and for generating refrig- .erant vapor under the effect of said heating` means, and means for transferring heat from the hot weak liquor returning to the storage means to the cold Astrongliquor flowing from said storage means. l

12. In an absor tion apparatus a generator system comprising `boiler, an analyzer, a re A ceiver, thermosiphon means for conveying liquor from the bottom of said analyzer to said boiler, a conduit for conducting vapor from said boiler to a point below the liquid levell in the analyzer,

Vsaidreceiver to said boiler and from said boiler back to said `receiversaid fluid circuit including a' therinosiphon element for veil'ecting said .circulation and including ameans for exchanging heat between the fluid flowing from the-receiver, to the boiler and the uid flowing from the boiler to the receiver.

9. Absorption apparatus comprising a highi pressure part and a low pressure part, transfer mechanism for' periodicallyeifecting a transfer,

of uid therebetween comprising a vent connection `between said high and lowy pressure parts high and low pressure parts, valves for controlling said connections and snapacting mecha-V nism for controlling lsaid valves and a float responsive tochangesinllquid level in one of said parts for operatingsaid snap-acting mechanism.

i@ 14. In an absorption apparatus, an absorber system, a` generator system, connections therebetween operable for periodicallyeffecting transj fer of weak liquor from the generator system to the absorber system and strong liquor from the and Va pair of liquid connections between said ,`10..An absorptionl apparatus of thetype hav- `ing an. absorber system-normally operating at a relatively low pressure and a generator systemnormally operating at a relatively high pressure duringthe same time` that said absorberrsystem is operating, said generator system comprising a boiler, an analyzer, a receiver, a conduit for conducting strong liquor from the receiverto the analyzer, thermosiphon. means for conveying liquor from the bottom 4of the analyzer. to said.'

` boiler, a conduit for conductingvvapor from said boiler to a point below` the liquidlevel 'in the analyzer, and a conduit for conducting weak liquor from the boiler4 to the bottom of said reeiver, said'strong liquor conduit from said receiver to said analyzer! and said weak` liquor conduitrfmm said boiler'iwthe bottom of sal! receiver, being arranged in heat exchangerelationf absorber system to the generator system, means ,A for heating at least part of the generator system so as tofgenerate refrigerant vapor, said gen-A erator system having a portion thereof arranged for storing weak liquor at a temperature. matel `rially less than that prevailing in that part of said generator system in which refrigerant vapor is generated, means for removing heat from said 4 Weak ..1iquor before storing the same, and means in said weak liquor storing portion ofthe generator system, for pe1'lodically,opening the connection between the vgenerator systemv and `the absorber system so as to utilize pressure Awithin' the generator system for transferring said stored weak liquor to the absorber system and to permit the transfer to the generator system 'of aV kfresh charge of strong liquor.

. 7,/ 15. In. an absorption apparatus, a generator system comprising a liquid receiver, an analyzer,

a boiler,v a vent between the upper -partofffsaid l analyzer and said receiver, a condenserg'a vaporous refrigerant conduit including ayrectiiier between. said analyzer y'and said condenser, and

auid circuit including said receiver, said ana-` lyzer, andv said boiler. and including lconnections forcirculating fluid 4therebetweernfsaid oonnec-y u 'tions including a strong liquor line betweenan intermediate part of said receiver and said analyzer and a Weak liquor line between the bottom part of said boiler and said receiver, said strong and Weak liquor lines being associated for the interchange of heat therebetween, and said connections including thermosiphon means between the bottom of said analyzer and the upper part of said boiler `for eiecting said circulation, and

including a""vapo'r conduit between the upper 10 part of said boiler and the part of said analyzer A below the liquid level therein.

16. In an absorption apparatus of the type having a generatorsystem normally operating at a relatively high pressure, and an absorber system normally operating at a relatively low pressure during the same time thatv said generator system is operating, means for separating said systems so as to enable a higher pressure to be produced in the generator system than in the absorber system,`said separating means operating periodically for equalizing the pressures between the two systems, said generator system comprising a iiuid circuit including means for storing strong 'and weak, liquor and a thermosiphon element, and connections between said storing means and said thermosiphon element including means for transferring heat fromthe'hot weak liquor returning to the storing means to the cold strong liquor coming from the storing means, and means for heating'vsaid thermosiphon element so as to generate vapor therein and to eiect circulation of liquor through said circuits.

HENRY A. BURGGRABE. 

